In thermally assisted magnetic/optical recording, information bits are recorded to a storage layer of a storage media at elevated temperatures. Generally, a spot or area on the storage medium is heated to reduce its coercivity sufficiently so that an applied magnetic field or optical write signal can record data to the storage medium.
One particular technique for heating the spot or area includes focusing energy at a surface of the storage medium using an optical antenna or aperture, sometimes referred to as a near-field optical transducer (NFT), to achieve a tiny confined optical spot beyond a diffraction limit of an optical lens. An optical antenna relies on excitation of local surface plasmon (LSP) at an interface between a metal of free electrons and a dielectric material. The NFT is designed to have a size that excites the LSP at a desired light wavelength (λ). At the interface between the dielectric material and the metal, collective oscillations of electrons in the metal increase interaction between electrons in the metal and the light wave and induce a high electrical field to develop around the metal. A portion of the field can tunnel into an adjacent storage medium, which absorbs associated energy, raising the temperature of the adjacent storage medium locally. The increased temperature can be used for heat-assisted recording.
Unfortunately, the optical antenna can dissipate energy. Further, the heat-assisted recording device can be sensitive to head-media space (HMS) and to fabrication variances in the shape of antenna. Embodiments disclosed herein can provide solutions to these and other problems, and offer other advantages over the prior art.